Private Sub GcSpreadGrid1_PreviewKeyDown(sender As Object, e As KeyEventArgs)
　　If TypeOf GcSpreadGrid1.ActiveCell.CellType Is CheckBoxCellType AndAlso GcSpreadGrid1.ActiveCell.Locked = True OrElse e.Key = Key.OemPlus OrElse e.Key = Key.Add OrElse e.Key = Key.OemMinus OrElse e.Key = Key.Subtract Then
　　　　e.Handled = True
　　End If
End Sub

public MainWindow()
{
　　InitializeComponent();
　　GcSpreadGrid1.PreviewKeyDown += GcSpreadGrid1_PreviewKeyDown;
}

private void GcSpreadGrid1_PreviewKeyDown(object sender, KeyEventArgs e) 
{ 
　　if (GcSpreadGrid1.ActiveCell.CellType is CheckBoxCellType && GcSpreadGrid1.ActiveCell.Locked == true 
　　　　|| e.Key == Key.OemPlus || e.Key == Key.Add || e.Key == Key.OemMinus || e.Key == Key.Subtract) 
　　{ 
　　　　e.Handled = true; 
　　} 
}